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Finding the Fourth Proportional to 685.77, 1,028.98 and 425.71

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Solution

The fourth proportional to 685.77, 1,028.98 and 425.71 is: 638.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.77 : 1,028.98 = 425.71 : x
  2. Step 2: Convert to fraction form
    685.77/1,028.98 = 425.71/x
  3. Step 3: Cross multiply
    685.77x = 1,028.98 × 425.71
  4. Step 4: Simplify right side
    685.77x = 438,041.91
  5. Step 5: Solve for x
    x = 438,041.91/685.77
  6. Step 6: Final answer
    x = 638.76

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.